Anodic protection is designed to reduce and prevent the effects of galvanic corrosion on the hull of the ship and its units. Zinc anodes are used in salt water. If you store the vessel ashore, protective anodes oxidize and galvanic corrosion protection level becomes very low. Before the descent to water anodes should be cleaned with sandpaper to remove all oxides. Recommended replacing the anode if it dropped more than 1/3 of its original size.